The actinomycete genus Kitasatospora has a developing history of producing biologically active metabolites, especially those with cancer cell growth inhibitory properties. An early example of the latter was the isolation of the anticancer antibiotic terpentecin from a soil Kitasatospora sp. (strain MF730-N6) by Umezawa and colleagues in 1985.2 That advance was quickly followed by the isolation of anticancer carbolines from Kitasatospora setae3a,b cultured from a Spitsbergen soil sample.4 In 1993, the stereochemically undefined cyclodepsipeptide respirantin (1) was isolated from a Kitasatospora sp. during an examination of its constituents for insecticidal activity.5 Interestingly, in an investigation of endophytic actinomycetes on Taxus baccata plants, a Kitasatospora sp. (strain P & U 22869) was isolated and found to produce taxol and related taxanes.6 More recently, Kitasatospora spp. have been found to produce yeast-like pleiotropic drug-resistant pump constituents,7 proteasome inhibitors designated tyropeptins A and B,8 and bafilomycin-like antifungal compounds9; more recently, K. cheerisanensis was found to contain the cytotoxic bafilomycin C1-amide.10 The bafilomycins represent a group of 16-membered macrocyclic lactones isolated from K. setae and several streptomyces species and are very strong cancer-cell-growth inhibitors.11a-h 